In such institutions as hospitals, medical and other laboratories, in industry, financing houses, wholesalers' offices, warehouses and the like, where computers are used for storage and interpretation of data observed or otherwise compiled, it is customary to use a writing system comprising writing units with keyboards and record forming means, whereby it is possible both to write out information in plain language on the writing units and at the same time, by means of interconnected record forming means, such as a perforator, to effect a simultaneous recording of the data pertinent in coded form on a perforated tape or other record means. The record means can be used for feeding the information into a computer, or, where appropriate, such coded data being generated by the writing units can be connected directly on line with the computer. The information which is to be entered into the writing system has generally been compiled in plain language on a record sheet or other suitable medium for checking purposes, and as a recording medium for entry of the data it is customary to use a card, ledger page or the like, which is specific to the person, order, account etc. concerned. Also, when the relevant data are first recorded, the recording medium is also provided with some corresponding identifying or key data in plain language when being positioned on the platen of the writer unit by itself or in front of the record sheet.
Every time recording in such a writing system is to commence, specific data which identify the card and thus the patient, customer, etc. concerned, have to be keyed-in by the operator of the writer unit, in order that this information may be stored in the computer under the same address and, subsequently, when required, be retrieved under this address. It is, in other words, necessary for the operator to key-in the same identification data anew every time a new set of information compiled on the same card is to be entered into the writing system, in order that the relevant identification data shall be transferred to the record forming means or the computer. Not only is this a laborious process, but it also involves the risk of an address being wrongly recorded because of an error on the part of the keyboard operator. This may have very serious consequences if, for example, diagnostic data are recorded under the address of a patient other then the one to whom it relates.